Vessel intervention procedures often comprise the task of positioning an intervention device inside a vessel prior to further procedural steps. For example, in TAVI interventions, a very critical point is the precise positioning of an implantable device under fluoroscopy prior to fixation or deployment of the implantable device. To achieve such positioning, an angiogram, i.e. an X-ray image acquisition with contrast agent being present in a vessel region of interest, is typically performed in order to determine an optimal projection for fixation of the implantable device, i.e. for example for deployment of a replacement aortic valve. An image featuring for example good contrast may be manually selected, stored and subsequently used as pre-implant reference image. The contrast agent injection may be achieved through a so-called pig-tail catheter placed in the aortic root.
In order to facilitate accurate positioning, road mapping or outlining methods have been proposed e.g. in WO 2010067300 A1. Therein, a live view, i.e. a fluoroscopy X-ray image without contrast agent being present in the vessel region of interest, may be superimposed with an anatomic representation of the aortic root such as contours of the aortic root as extracted from a reference aortogram, a model derived from 3D-pre-interventional data, combinations thereof, etc. The anatomic representation should be correctly registered to the live images, such live registration process being often referred to as tracking.